/* minigzip.c -- simulate gzip using the zlib compression library

 * Copyright (C) 1995-2005 Jean-loup Gailly.

 * For conditions of distribution and use, see copyright notice in zlib.h

 */

/*

 * minigzip is a minimal implementation of the gzip utility. This is

 * only an example of using zlib and isn't meant to replace the

 * full-featured gzip. No attempt is made to deal with file systems

 * limiting names to 14 or 8+3 characters, etc... Error checking is

 * very limited. So use minigzip only for testing; use gzip for the

 * real thing. On MSDOS, use only on file names without extension

 * or in pipe mode.

 */

/* @(#) $Id$ */

#include <stdio.h>

#include "zlib.h"

#ifdef STDC

#  include <string.h>

#  include <stdlib.h>

#endif

#ifdef USE_MMAP

#  include <sys/types.h>

#  include <sys/mman.h>

#  include <sys/stat.h>

#endif

#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)

#  include <fcntl.h>

#  include <io.h>

#  define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)

#else

#  define SET_BINARY_MODE(file)

#endif

#ifdef VMS

#  define unlink delete

#  define GZ_SUFFIX "-gz"

#endif

#ifdef RISCOS

#  define unlink remove

#  define GZ_SUFFIX "-gz"

#  define fileno(file) file->__file

#endif

#if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os

#  include <unix.h> /* for fileno */

#endif

#ifndef WIN32 /* unlink already in stdio.h for WIN32 */

  extern int unlink OF((const char *));

#endif

#ifndef GZ_SUFFIX

#  define GZ_SUFFIX ".gz"

#endif

#define SUFFIX_LEN (sizeof(GZ_SUFFIX)-1)

#define BUFLEN      16384

#define MAX_NAME_LEN 1024

#ifdef MAXSEG_64K

#  define local static

   /* Needed for systems with limitation on stack size. */

#else

#  define local

#endif

char *prog;

void error            OF((const char *msg));

void gz_compress      OF((FILE   *in, gzFile out));

#ifdef USE_MMAP

int  gz_compress_mmap OF((FILE   *in, gzFile out));

#endif

void gz_uncompress    OF((gzFile in, FILE   *out));

void file_compress    OF((char  *file, char *mode));

void file_uncompress  OF((char  *file));

int  main             OF((int argc, char *argv[]));

/* ===========================================================================

 * Display error message and exit

 */

void error(msg)

    const char *msg;

{

    fprintf(stderr, "%s: %s\n", prog, msg);

    exit(1);

}

/* ===========================================================================

 * Compress input to output then close both files.

 */

void gz_compress(in, out)

    FILE   *in;

    gzFile out;

{

    local char buf[BUFLEN];

    int len;

    int err;

#ifdef USE_MMAP

    /* Try first compressing with mmap. If mmap fails (minigzip used in a

     * pipe), use the normal fread loop.

     */

    if (gz_compress_mmap(in, out) == Z_OK) return;

#endif

    for (;;) {

        len = (int)fread(buf, 1, sizeof(buf), in);

        if (ferror(in)) {

            perror("fread");

            exit(1);

        }

        if (len == 0) break;

        if (gzwrite(out, buf, (unsigned)len) != len) error(gzerror(out, &err));

    }

    fclose(in);

    if (gzclose(out) != Z_OK) error("failed gzclose");

}

#ifdef USE_MMAP /* MMAP version, Miguel Albrecht <malbrech@eso.org> */

/* Try compressing the input file at once using mmap. Return Z_OK if

 * if success, Z_ERRNO otherwise.

 */

int gz_compress_mmap(in, out)

    FILE   *in;

    gzFile out;

{

    int len;

    int err;

    int ifd = fileno(in);

    caddr_t buf;    /* mmap'ed buffer for the entire input file */

    off_t buf_len;  /* length of the input file */

    struct stat sb;

    /* Determine the size of the file, needed for mmap: */

    if (fstat(ifd, &sb) < 0) return Z_ERRNO;

    buf_len = sb.st_size;

    if (buf_len <= 0) return Z_ERRNO;

    /* Now do the actual mmap: */

    buf = mmap((caddr_t) 0, buf_len, PROT_READ, MAP_SHARED, ifd, (off_t)0);

    if (buf == (caddr_t)(-1)) return Z_ERRNO;

    /* Compress the whole file at once: */

    len = gzwrite(out, (char *)buf, (unsigned)buf_len);

    if (len != (int)buf_len) error(gzerror(out, &err));

    munmap(buf, buf_len);

    fclose(in);

    if (gzclose(out) != Z_OK) error("failed gzclose");

    return Z_OK;

}

#endif /* USE_MMAP */

/* ===========================================================================

 * Uncompress input to output then close both files.

 */

void gz_uncompress(in, out)

    gzFile in;

    FILE   *out;

{

    local char buf[BUFLEN];

    int len;

    int err;

    for (;;) {

        len = gzread(in, buf, sizeof(buf));

        if (len < 0) error (gzerror(in, &err));

        if (len == 0) break;

        if ((int)fwrite(buf, 1, (unsigned)len, out) != len) {

            error("failed fwrite");

        }

    }

    if (fclose(out)) error("failed fclose");

    if (gzclose(in) != Z_OK) error("failed gzclose");

}

/* ===========================================================================

 * Compress the given file: create a corresponding .gz file and remove the

 * original.

 */

void file_compress(file, mode)

    char  *file;

    char  *mode;

{

    local char outfile[MAX_NAME_LEN];

    FILE  *in;

    gzFile out;

    strcpy(outfile, file);

    strcat(outfile, GZ_SUFFIX);

    in = fopen(file, "rb");

    if (in == NULL) {

        perror(file);

        exit(1);

    }

    out = gzopen(outfile, mode);

    if (out == NULL) {

        fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);

        exit(1);

    }

    gz_compress(in, out);

    unlink(file);

}

/* ===========================================================================

 * Uncompress the given file and remove the original.

 */

void file_uncompress(file)

    char  *file;

{

    local char buf[MAX_NAME_LEN];

    char *infile, *outfile;

    FILE  *out;

    gzFile in;

    uInt len = (uInt)strlen(file);

    strcpy(buf, file);

    if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) {

        infile = file;

        outfile = buf;

        outfile[len-3] = '\0';

    } else {

        outfile = file;

        infile = buf;

        strcat(infile, GZ_SUFFIX);

    }

    in = gzopen(infile, "rb");

    if (in == NULL) {

        fprintf(stderr, "%s: can't gzopen %s\n", prog, infile);

        exit(1);

    }

    out = fopen(outfile, "wb");

    if (out == NULL) {

        perror(file);

        exit(1);

    }

    gz_uncompress(in, out);

    unlink(infile);

}

/* ===========================================================================

 * Usage:  minigzip [-d] [-f] [-h] [-r] [-1 to -9] [files...]

 *   -d : decompress

 *   -f : compress with Z_FILTERED

 *   -h : compress with Z_HUFFMAN_ONLY

 *   -r : compress with Z_RLE

 *   -1 to -9 : compression level

 */

int main(argc, argv)

    int argc;

    char *argv[];

{

    int uncompr = 0;

    gzFile file;

    char outmode[20];

    strcpy(outmode, "wb6 ");

    prog = argv[0];

    argc--, argv++;

    while (argc > 0) {

      if (strcmp(*argv, "-d") == 0)

        uncompr = 1;

      else if (strcmp(*argv, "-f") == 0)

        outmode[3] = 'f';

      else if (strcmp(*argv, "-h") == 0)

        outmode[3] = 'h';

      else if (strcmp(*argv, "-r") == 0)

        outmode[3] = 'R';

      else if ((*argv)[0] == '-' && (*argv)[1] >= '1' && (*argv)[1] <= '9' &&

               (*argv)[2] == 0)

        outmode[2] = (*argv)[1];

      else

        break;

      argc--, argv++;

    }

    if (outmode[3] == ' ')

        outmode[3] = 0;

    if (argc == 0) {

        SET_BINARY_MODE(stdin);

        SET_BINARY_MODE(stdout);

        if (uncompr) {

            file = gzdopen(fileno(stdin), "rb");

            if (file == NULL) error("can't gzdopen stdin");

            gz_uncompress(file, stdout);

        } else {

            file = gzdopen(fileno(stdout), outmode);

            if (file == NULL) error("can't gzdopen stdout");

            gz_compress(stdin, file);

        }

    } else {

        do {

            if (uncompr) {

                file_uncompress(*argv);

            } else {

                file_compress(*argv, outmode);

            }

        } while (argv++, --argc);

    }

    return 0;

}